The invention is based on a fuel injection system for internal combustion engines. In one such fuel injection system, known from German Patent Disclosure DE 196 24 001 A1, the valve chamber in a first version communicates with the control chamber without any reduction in cross section. The control valve, upon actuation by the piezoelectric actuator, either completely opens the outflow cross section toward the outflow conduit or closes it. In a further version, the valve chamber communicates with the control chamber via a connecting conduit, and this connecting conduit is coaxial with the valve seat on the side toward the outflow conduit. By actuation of the control valve member by the piezoelectric actuator, either the outflow cross section from the valve chamber to the outflow conduit is completely opened or closed, or to attain a preinjection the control valve member is moved from the valve seat toward the outflow conduit so that the connecting conduit will enter the valve chamber; as a consequence of this motion, the control chamber is briefly opened toward the outflow conduit via the valve chamber. For an ensuing main injection, the control valve member is moved to a middle position, in which both the cross section toward the outflow conduit and the cross section of the connecting conduit into the valve chamber are opened completely. This embodiment has the disadvantage that to relieve the pressure in the control chamber, only a single geometrically defined outflow cross section toward the outflow conduit is available. The quantity of the preinjection, in the second version described, is such that the adjusting speed of the control valve member by the piezoelectric actuator and the geometrically defined travel of the control valve member are defined variables for the degree of relief of the pressure in the control chamber. In particular, the maximum relief cross section is the same size for both the relief for the preinjection and the relief for the main injection, which is disadvantageous from the standpoint of fine adaptation of the opening speed of the injection valve in various operating states.